The heat in the Formula One world championship battle was turned up a notch at the Azerbaijan Grand Prix when Sebastian Vettel appeared to intentionally drive his Ferrari into Lewis Hamilton's Mercedes.
Red Bull's Daniel Ricciardo won what was a chaotic race.
Formula One championship leader Sebastian Vettel finishing fourth after being penalised for swerving into rival Lewis Hamilton who came home in fifth.
Under the safety car, then race-leader Hamilton slowed suddenly and the following Vettel could not avoid making contact from behind.
Vettel reacted to what he deemed to be brake-testing by immediately drawing level with Hamilton and turning his car into his rival in a deliberate act of revenge.
Hamilton later lost his lead having to pit to re-fix his head restraint while Vettel, issued a 10-second stop-and-go penalty for dangerous driving in hitting Hamilton, managed to leap his title rival.
Vettel's fourth-place finish to Hamilton's fifth extended the German's standings lead to 14 points.
"I didn't brake check him at all," Hamilton told British broadcaster Channel 4.
"For him to pretty much get away with driving into another driver is a disgrace. I think he disgraced himself today.
"If he wants to prove he is a man we should do it out of the car. Imagine all the young kids watching today, seeing that kind of behaviour from a world champion."
"I have no doubt he brake-checked me," Vettel said.
"I didn't run into the back of him on purpose. I think it was very clear. In the end we are racing with men. If one of us gets a penalty, we both do. We are both grown up men. We want to race wheel to wheel."
The pair had previously spoken in high regard of each other in the title race, in contrast to the frequent verbal digs Hamilton gave former teammate Nico Rosberg during their duels in previous seasons.
Vettel perhaps extended the first hint of an olive branch, saying: "The championship battle is still respectful I don't have a problem with him, I think today's action was wrong."